It is essential that this game is in your collection (hehehe) as it could be the greatest RTS ever released.
It combines an historically accurate turn-based dynasty building mode with stunning real-time battles than can feature over 10,000 on the battlefield.
Go on crusades, assasinate your heir to allow your better son to take over, negotiate alliances, bribe rebels to your cause, you name it, you can do it.
The price is just amazing, I don't know how Activision can afford to make so many great games only $15!
Don't buy in to the over-rated, content lacking Age of Empires series, choose Total War!